Portable coin collector for telephone systems



June 29, 1948. L. E. VAN DAMME 2,444,074

PORTABLE COIN COLLECTOR TELEPHONE SYSTEMS Filed June 21, 1946 W n/70k L.E. VAN DAMME zq f A 7' TORNEV Patented June 29, 1948 PORTABLE COINCOLLECTOR FOR TELEPHONE SYSTEMS l LouisE. Van Dammc. u nu N L, ossignorto Bell Telephone Laboratories, Incorporated, New York, N. Y acorporation of New York Application June 21, 1946, Serial No. 678,225

r This invention relates to telephone ystems and more pa t cularly to pr-payment telephone ystem of the portuble type.

In lar e nstituti ns. particula y t ose whic cater to the s ck anddisabled, othe faciliti s are orov-idedwncreby telephone calls may berec ived and originated .o-t thehedside of those patients who, becauseof, their 'lnfiilnltics. are unable to avail themselves of the regular.communication facilities. Such other facilities involve portable instumentollties which m y be carried. or othersc rop lled to the bedside ofa patient and p u ssd into a convcnientlylocotedjuuk tcmninul of sotclephone line. The patients utili n th e facilities are usually billedat regular intervals for telephone culls originated by them. Thispractice imposes upon the institution the bu d n of keeping records oithe numerous outgoing. calls undof compiling individual bills to berendered to each of the patients making such calls. In order to relievethe institutions of this task and to other-w se p ov th telephoneservice wh ch is furnished n .a p rtab e basis it has been pr pos d thatsuch service be Provided on a pro-payment basis. In order to providesuch service it is essential that the portable unit include thenecessary apparatus for receiying co ms which are (1&- ho lted. inayment f r calls to beorlginated, and for disp sing of such. coins in aordance with usual practice. In other words, the portable unit mustembrace all th s nt als of a coin box telephone station. t l v Sincesuch portable units are plug-ended to tooilitutc their nnect n to thetel phone lines by way of conveniently located jack t pe line terminals,it is e sential that, at the termination ofo call originated by meansvof the portable coin box station, the connection of the plug with theluck remain undisturbed until the coin disposal apparatus has beenoperated in the usualmanner in order that the deposited coins may becollected, or refunded as required. V l

In a, contending application, serial No. 676,610, filed June 14, 1946,there is disclosed a telephone system of the prepayment portable whichprovides for the automatic collection of coins deposited in a portablecoin collector in. [payment for a. call originated jail; the portablestation, in the event the portable unit is disassoclaited from atelephone line before the coinshave been disposed of in the usualmanner. 7

It is the object of this invention to provide an improved portablc coinvcollector of "the general ype disclosed in the albovcsmentlonedcoplandln application Whichinsures the automatic collec- 7 C aims. (01.no-s3) 2 tion of coins. deposited in the portable unit, in response tothe disconnection of the portable unit from .2, telephone line prior tothe disposal of the coins in the usual manner.

This object is attained in accordance with a torture o the invention byutilizin in the portublc uni a vacuum tub -r luy-condenser oomblnu iun wich functions automatically when the portabl unit is isassocioted fr m atelephone line to connect the coin co r l mag t, or relay to a. localsou ce of power. such as a, battery, to cause the coin magnet to operatein such a maner on '99 effect the collection of the deposited More paricu a y. the coi g t. Or lay is normally connected between ground andthe tip conductor of the line when the portable coin collector isconnected to the line outlet and a. wi ha be n depu itedin the coinreceptacle, by way of book contacts of a. relay the operation of whichis controlled by the vacuum tube. The vacuum tube. is of the tri gertype and has its culihodfi and lQQntrol electrode short-circuitedthrough the contacts of the jack and plug connectors by which theportable unit is connected to the telephone line and has its plate, oranode connected in series with the winding of the relay. Prior to thedisoonncction of th portable unit from the line the condenser is.charged up to the full voltage of the local battery and this voltageappears across th main gap of the vacuum tube. Thetube, however, doesnot fire since this potentlulls below that required to break down themain gap. This same potential is also connected a ros the control our ofthe tube but since this gap as stated above, is short-oircuited, thetube does not fire.- When, the portable unit is disassocioted from theline by tho withdrawal of the plug from thejuclr terminal of the line,the short circuit is removed lirom thecontrol can ofthe tube and thetube fires from the-potential across the condenser. With the control gapfired, the main ap will also fire causing current to flow in the anodeircuit which includes the control relay. This relay operates andtransfers the coin control relay from the tip conductor of the line tothe local battery cousins the coin control relay to opertlt and coll ctthe deposited coins.

This. and other features of the invention will be hotter understood fromthe tollowing descriptions when read in connection with the accompanyingdrawing which is a circuit diagram illustrating a [portable coincollecto embodyin the features. of the invention. 7

"To the. left of the drawing an operators telephone cord circuit isschematically illustrated.

3 Only those elements of the cord which are essential to a completeunderstanding of the invention are indicated. A line L is shownterminating at a telephone exchange in a jack I and at a remote stationin two jack outlets I2 and I3. These outlets are multipled together andobviously need not be limited in number to the two shown. In practice,these outlets would be located at convenient places in an institution orhospital, usually in close proximity to the beds in a ward or perhaps ina private room. The apparatus shown to the right of the jack I2 includesthose elements of the portable coin collector of this invention. A coincollector of this type may be mounted on a wheel carrier which can bepropelled from one location to another and the plug terminal thereof maybe provided with a cable of suitable length and Wound on a reel therebyaccommodating the collector to various distances between the telephoneline outlets and the location of the patients wishing to employ it.

A detailed description of the operation of the system disclosed in thedrawing follows:

Automatic coin collection .It will now be assumed that a patient desiresto initiate an outgoing call by means of the ports able coin collectorPC and that the jack I2 is nearest the point at which the patient islocated.

An attendant would roll the portable unit up to y the bedside of thepatient and insert the plug I4 thereof into the jack I2 of the line L.The patient then inserts a coin in the coin box of the portable unit andlifts the telephone from its support in the usual manner of originatinga, telephone call from a pay station. These operations and the resultsthereof are well known in the art and require no further discussion. Itwill now be assumed that the coin deposited by the patient has beenreturned, if insufiiclent to cover the toll for the connection desired,and that the correct amount in coins has been deposited in the coin boxand further, that the desired connection has been completed and theconversation period ended. In theevent that the calling party hangs upthe telephone and the plug I I is not immediately withdrawn from thejack, the deposited coins are automatically collected in the usualmanner if the call has been completed on an automatic basis and in thefollowing mannerif the connection has been completed by an operator at acentral oflice. The operator actuates the coin collect key I5 so as toconnect positive coin collect battery I6 to the tip conductor of hercord. Coin collect current then traverses a path from battery I6, overthe closed contacts of key I5, tip contacts of plug I I and jack "I,contact I8 of the jack outlet I2 of line L, contact I9 of plug I4, leftback contact and armature of relay in the portable unit, coin contacts2| of the collector PC, windings of coin relay 22, plug contact 23, andjack contact 24 to ground. The direction of the current in this circuitis such as to cause the coin relay 22 to operate in a manner to causethe deposited coins to be collected.

It will now be assumed that prior to restoring the telephone of theportable collector PC to its switchhook the calling party, inadvertentlyor otherwise, withdraws the plug I4 from jack I2. Obviously, under thiscondition and with no pro vision to guard against such acontingency,th'e deposited coins remain in the hopper of the coin boxwithout having been disposed or since the line to the exchange isseverad at the contacts of the plug I4 and jack I2. It will be observedthat should a subsequent call be originated and the operator shouldperform a refund operation on a coin collector of the usual type, allthe coins deposited on a previously completed call would be refunded andwould come into the possession of the party making the subsequent call.Applicants invention precludes this possibility.

It will be observed that While the plug I4 is in the jack I2 and duringthe pendency of the established connection condenser 26 is charged up tothe voltage of the local battery 21. The charging circuit for condenser26 is traced from the right terminal of battery 21, over resistance 28,condenser 26, contact 29 of plug I4, contact 36 of jack I2, contact 24of jack I2 and contact 23 of plug I4 to the left terminal of battery 21.This same potential appears across the main gap, anode 3|, cathode 32,of tube 33 through the winding of control relay 20. The tube 33 does notfire since this potential is below that required to break down the maingap of the tube. This same potential is connected across the controlgap, cathode 32, control electrode 34 of tube 33 through-resistances 36and 28 but the control gap is'short-circuited through the contacts 29and 31 of plug and contacts 30 and 38 of jack I2 and therefore, the tubedoes not fire by way of the control gap. However, when the'plug I4 iswithdrawn from jack I2, the short circuit is removed from the controlgap of the tube 33 so that the tube fires from the potential acrosscondenser 26 through resistances 28 and 36. With the control gap fired,the main gap of the tube is rendered conductive causing current to flowthrough the windingof relay 20.

Relay 20 operates when the tube 33 fires and at its inner right armatureandfront contact closes a holding circuit for itself through resistance40 and condenser 26. At its inner left armature and back contact relay20 disconnects the coin relay 22 from the tip conductor of the portablecollector circuit and at its outer armature and front contactit connectsthe coin relay 22 across the local dry battery 21 through the filamentof resistance'lamp 4|. At its outer right armature and back contactrelay 20 removes the coin relay back contact 42 from the conductor .43.Relay 22' now operates in such a manner as to cause the deposited coinsto be collected.

With relay 20 operated, the potential across the main gap of the tube33'is reduced belowits sustaining voltage and the tube extinguishes.Relay 20, however, remains operated for approximately one-half seconduntil the condenser 26 is effective- 1y discharged, at which time therelay 20 releases and restores the circuit to normal condition. Theconnections of the tipconductorand' conductor 43 are open during theoperation of relay 20 to prevent interference with the automatic collectfeature of the portable collector circuit should plug I l be partiallywithdrawn from jack I2 in such amanner as to open theplugand jack'contacts 29, 31-30, '38 while the other contacts of the jack I2 andplug l4 remain closed.

Resistance 28 is made high in value to prevent false operation of tube'33 under plugfumbling conditions. I

' Incoming call Ringing current from: the central office opera ates theline, ringer 60 and the ringer 5I if the plug, I4 is inserted in thejack I2. Ringing is tripped in the usual manner when the switchhook ofthe portable unit is raised.

Ifthe' call isto be held while the portable unit is moved to anotherlocation, the hold key 64 is operated while: the switchliookisr'rai'sedl Ions-removesa short, circuit from. the winding of relay 55which relay then. operates from the central ofllcebattery 56 and groundin serieswith relay 51- and the closed loop at the portable substation.Relay performs n useful function at this time. Relay'55 operateshowever,and completes an obvious operating circuit for relay 5B Relay 58 inoperating opens the short circuit around relay 55' at another point andtransfers: the oper= ating circuit of relay 55 from theringconductor ofthe connection tothe hold conductor 60. This connects relay 55 in.series with the lower winding oi relay 8-1 which relay also operatesfrom central oi-lice battery. Relay 51 releases at this time;

When relay" 6'loperates it closes a holdingcir- (nut-through its ownf-ront contact and armature; its upper winding and thenon-inducti-vewinding 63 across the tip and ring conductors on the central ofiic'eside of the line L. Relay 61 is now held operated on its upper windingaudits noninductive winding 63 directly across the line and on its lowerwinding in series with relay 55 and the-subset bridge. Relays 55" and58- remain operated' after the" hold key 54 isrestored; as long as thesubset switchhook is raised.

When plug It is removed from the jack I2, orif the subset switch-hookisrestored prior to the removal of plug 14 fromjack l2, relays 55 and '58release, but relay 6| remains held upon its upperWinding'onlyto-central'ofiice battery 5-9 and holds the central ofiiceconnection.

When the plug It is" reinserted in another jack, such as jack [3 atanother location and the switchhook of the portable substation israised, relay 5''! operates in series with the subset bridge andshortcircuits the upper winding, of relay Bl' causing relay 6| torelease, Relays 55 and 58 do not operate at this time since relay 55 isshortcircuit'e'd through the hold key 5 4 and. the back contact of.relay 58. The central oifice connection is now held in the usual mannerthrough the subset bridge. If the hold condition is applied and notrestored at the portable subset it may be released from the centraloffice. If the hold condition is applied during the course of a regularcall by inadvertent operation of the hold key 54, it may be released bymomentarily depressing and releasing the subset switchhook.

Outgoing call With plug I4 inserted in a jack such as l2 or l3 thedeposit of a coin in the coin receptacle will connect ground through thecoin relay 22 to the tip conductor of the line L as a signal to thecentral ofi'ice in accordance with usual practice. If the coin collectoris arranged for dial operation, the dial pulsing contacts (not shown)are kept short-circuited through the back contact 42 of the coin relay22 until a coin is deposited. At the completion of the call, theoperator or the 'dial central office equipment will collect or refundthe coin in the usual manner. The collection of the coin is eiiected ona manual connection as previously described, by the actuation of coincollect key l5 which connects positive collect battery iii to the tipconductor of the line L, whereas a coin refund is effected by theactuation of key which connects coin refund battery H to the tipconductor of the line.

It is apparent from the foregoing descriptions that the fraudulent orinadvertently false disposal of coins deposited in a portable coincollector is rendered impossible in a simple, reliable manner and with aminimum of apparatus.

1; The combination; in a telephone system, or a line and a. coincollectorremovably connected to said line, said coincoilectorincliiding'a local batfiery, a disposal' magnet normaliydiscomnected from-said battery, avacuum tube, means e-iibctive incidentto the connection of said coin collector to saidline for conditioningsaid vacuum tubef'or responseto' th'e disconnection of said coincollector-from said line, and means controlled by saidvaeuum: tubeincident ho its response to the disconnection of said coin collectorfrom said line ioi connecti-ng said coin disposal magnet to saidbattery;

2 The combination, ina telephone system, of a li neterminatingina jack,a portable coin collector havinga plug' for insertion in-said jnckwhereby saidcoin collector is removably connected to said line, saidcoin collector including a: local battery, a coin disposal magnet, avacuum tube having a normally sliort-circuited control gap,- ineans'normally' applying potential from said batterytotheshort-circuitedcontrol'gap of said tube, means efiective incident tothe withdrawal of said plug from said jackfor removing theshortcir cuitfrom the controP gapoi sa'id tubewhereby said tube is caused to-operate;and-means respon' sive to the operation of said tube for connecting saidcoindi-sposal magnet to'said battery 3". The combination; in a telephonesystem, or atelephone line, a portable coin box unit remov: ablyconnected to said line; said unit comprising a battery, a coin disposal"magnet normallydisconnected from said battery; and" means responsive tothe disconnection of said unit'fi'om' said line for" automaticallyconnecting said coin disposalmagnet tosaid battery comprising a vacuumtube having) an anode, cathode, and control electrode, a relay includedin the anode circuitof'said tube, a condenser for applying potentialfrom'said battery across theanode and control" electrodes of saidtubeand across'the cathode and control" electrodes of said tube, thepotential connected across the anode and cathode being of insufiicientmagnitude to cause said tube to fire, means normally short circuitingthe cathode and control electrode of said tube whereby the potentialapplied by said condenser to said anode and control electrode isrendered inefiective to cause said tube to fire, and means efiectiveincident to the removal of said unit from connection with said line forremoving the short circuit from the cathode and control electrode ofsaid tube to cause said tube to fire and to complete an operatingcircuit for said anode circuit relay.

4. In a portable coin collector having a plug connector for insertion ina jack terminal of a telephone line, a coin disposal magnet, a source ofpower, means responsive to the deposit of a coin in said collector forpreparing said coin disposal magnet for connection to said battery, avacuum tube, means controlled thereby for completing the connection ofsaid coin disposal magnet to said battery, means responsive to theinsertion of said plug connector into said jack terminal forconditioning said vacuum tube for operation, and means effective uponthe withdrawal of said plug connector from said jack terminal forcausing said vacuum tube to operate and to effect the operation of saidconnection completing means.

5. In a. portable coin collector having a plug connector for insertionin a jack terminal of a telephone line, a coin disposal magnet, a sourceof power, a vacuum tube having a control gap,

a condenser chargeable from said source, means including contacts ofsaid plug connector and said jack terminal efiective upon the insertionof said plug connector into said jack terminalfor connecting saidcondenser to said source of power and across the control gap of saidvacuum tube and for short-circuiting the control gap of said vacuum tubewhereby said condenser is charged and said vacuum tube is precluded fromoperation by Way of its control gap, said contact means functioning uponwithdrawal of said plug connector from said jack terminal to remove theshort circuit from the control gap of said vacuum tube so as to causesaid vacuum tube to operate on the condenser charge by wayv of itscontrol gap, and switching means responsive to the operation of saidvacuum tube for connecting said coin disposal magnet to said source ofpower.

- 6. The combination in a telephone system of a line, a jack terminatingsaid line at a remote point, a portable coin collector unit, a plugassociated therewith and inserted in saidjack whereby said unit isremovably connected to said line, said unit comprising a source ofpower, a condenser charged by said battery, a vacuum tube having anode,cathode and control electrodes, a relay connected across said condenserin series with the anode and cathode of said tube, a shortcircuitingpath for the cathode and control electrode of said tube includingcontacts of said plug and said jack, a coin disposal magnet normally onopen circuit with respect to said battery, and means controlled by saidrelay incident to the withdrawal of said plug from said jack forconnecting said coin disposal magnet to said battery, the withdrawal ofsaid plug from said jack causing'the opening of said short-circuitingpath, whereupon the charge on said condenser is eifec tively applied tothe cathode and control electrodesof said tube to cause said tube tofire and to the anode and cathode of said tube to sustain said'tube inits operated condition and to denser through the winding of said relaywhereupon said relay releases after a time interval to disconnect saidcoin disposal magnet from said battery.

'7. In a telephone system, a telephone exchange, a remote station, aline extending from said exchange and terminating at said remote stationin a plurality of line outlets, a portable substation at said remotestation, a connector associated with said portable substationcooperating with said line outlets for connecting said portablesubstation to said line, a holding bridge for said line, a first relayincluded in said substation, a second relay included in said substation,a hold key in said substation, the said first relay being normally shortcircuited by serially connected contacts of the said second relay and ofsaid hold key whereby said first relay is operated in response to theactuation of said hold key, means controlled by said first relay whenoperated for operating said second relay whereby the short circuit ofsaid first relay is maintained opened independent of the continuedoperation of said hold key, means responsive to the operation of saidsecond relay for connecting said holding bridge acrms said line, lockingmeans controlled by said connecting means for maintaining said holdinbridge connected to said line independent of said second relay wherebythe connector of said portable substation may be disconnected from saidline terminal to disconnect said portable substation from said linewithout disturbing the connection of said holding bridge to said line,and means included in said line responsive to the reconnection'of saidsubstation connector to one of said line terminals while the telephoneof said substation is removed from its support for releasing saidlocking means, whereupon said holding bridge is disconnected from saidline.

LOUIS E. VAN DAMME.

